U.S. patent application number 13/826569 was filed with the patent office on 2014-09-18 for fittingless pneumatic multiport selector valve for analytic instruments.
This patent application is currently assigned to Rosemount Analytical Inc.. The applicant listed for this patent is ROSEMOUNT ANALYTICAL INC.. Invention is credited to Shane Hale, Jason P. Pratt, Willis Watkins.
Application Number | 20140260538 13/826569 |
Document ID | / |
Family ID | 49617017 |
Filed Date | 2014-09-18 |
United States Patent
Application |
20140260538 |
Kind Code |
A1 |
Pratt; Jason P. ; et
al. |
September 18, 2014 |
FITTINGLESS PNEUMATIC MULTIPORT SELECTOR VALVE FOR ANALYTIC
INSTRUMENTS
Abstract
A pneumatic multiport selector valve and analytic instrument
employing said valve are provided. The valve includes a base having
a mounting surface configured to mount to the analytic instrument.
The mounting surface has a plurality of apertures therein for
coupling to flow conduits of the analytic instrument. At least one
piston plate has a number of apertures therethrough. The apertures
are configured to slidably receive respective pistons. Pistons are
disposed in respective apertures of the at least one piston plate.
A cushion layer is disposed between the at least one piston plate
and the base. The cushion layer has a plurality of apertures to
allow actuation gas therethrough. A plate clamps the at least one
piston plate to the base.
Inventors: |
Pratt; Jason P.; (Cypress,
TX) ; Hale; Shane; (Jersey Village, TX) ;
Watkins; Willis; (Cypress, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ROSEMOUNT ANALYTICAL INC. |
Houston |
TX |
US |
|
|
Assignee: |
Rosemount Analytical Inc.
Houston
TX
|
Family ID: |
49617017 |
Appl. No.: |
13/826569 |
Filed: |
March 14, 2013 |
Current U.S.
Class: |
73/23.42 ;
137/625.48 |
Current CPC
Class: |
F16K 11/00 20130101;
F16K 27/045 20130101; G01N 30/32 20130101; G01N 2030/328 20130101;
Y10T 137/86879 20150401 |
Class at
Publication: |
73/23.42 ;
137/625.48 |
International
Class: |
G01N 30/26 20060101
G01N030/26 |
Claims
1. A pneumatic multiport selector valve comprising: a base having a
mounting surface configured to mount to an analytic instrument, the
mounting surface having a plurality of apertures therein for
coupling to flow conduits of the analytic instrument; at least one
piston plate having a number of apertures therethrough, the
apertures being configured to slidably receive respective pistons;
a plurality of pistons disposed in respective apertures of the at
least one piston plate; a cushion layer disposed between the at
least one piston plate and the base, the cushion layer having a
plurality of apertures to allow actuation gas therethrough; and a
plate clamping the at least one piston plate to the base.
2. The pneumatic multiport selector valve of claim 1, and wherein
the cushion layer is isolated from the actuation gas.
3. The pneumatic multiport selector valve of claim 2, wherein the
cushion layer is porous.
4. The pneumatic multiport selector valve of claim 3, wherein the
cushion layer is formed of a meta-aramid material.
5. The pneumatic multiport selector valve of claim 3, and further
comprising a plurality of seals isolating the cushion layer from
the actuation gas.
6. The pneumatic multiport selector valve of claim 1, wherein the
plate is urged toward the base by a threaded member engaged with
the base.
7. The pneumatic multiport selector valve of claim 6, wherein the
threaded member is a bolt having threads engaged within the
base.
8. The pneumatic multiport selector valve of claim 6, wherein the
threaded member is torqued to a specified amount.
9. The pneumatic multiport selector valve of claim 1, wherein the
base includes a flange having a plurality of mounting holes
therethrough.
10. The pneumatic multiport selector valve of claim 9, wherein the
mounting holes are evenly distributed about a periphery of the
flange to facilitate even sealing force to the mounting
surface.
11. The pneumatic multiport valve of claim 1, wherein the mounting
surface is substantially planar and wherein fluidic connections for
all ports and actuation gas couplings are performed
simultaneously.
12. The pneumatic multiport valve of claim 1, wherein the mounting
surface has a plurality of bores therein, the plurality of bore
being configured to receive alignment pins of an analytic
instrument.
13. An analytic instrument comprising a base plate having a
plurality of fluid flow apertures arranged thereon; a pneumatic
multiport selector valve, the first pneumatic multiport selector
valve having: a base having a mounted surface mounted to the base
plate, the mounting surface having a plurality of apertures therein
coupled to respective fluid flow apertures of the base plate; at
least one piston plate having a number of apertures therethrough,
the apertures being configured to slidably receive respective
pistons; a plurality of pistons disposed in respective apertures of
the at least one piston plate; a cushion layer disposed between the
at least one piston plate and the base, the cushion layer having a
plurality of apertures to allow actuation gas therethrough; and a
plate clamping the at least one piston plate to the base.
14. The analytic instrument of claim 13, wherein the base of the
first pneumatic multiport valve includes a flange having a
plurality of mounting hole, with threaded connector passing through
each respective mounting hole to engage with the base.
15. The analytic instrument of claim 14, wherein the plate is urged
toward the base by a threaded member engaged with the base.
16. The analytic instrument of claim 15, wherein the threaded
member is a bolt passing through the center of the plate and being
threaded into the base of the multiport selector valve.
17. The analytic instrument of claim 13, wherein an o-ring couples
each aperture of the base of the multiport selector valve to a
respective aperture of the base plate of the analytic instrument.
Description
BACKGROUND
[0001] Analytic instruments are used in a number of applications to
quantitatively and/or qualitatively analyze a sample of interest.
Analytic instruments are often found in laboratories and are
sometimes employed within processing operations. As used herein, an
analytic instrument is any device, system or arrangement that is
able to receive a sample of interest and provide an indication of
some aspect of the sample of interest. Analytic instruments
include, without limitation, process gas analyzers, NO/NOx
analyzers, hydrocarbon analyzers, continuous emission monitoring
systems and process gas chromatographs.
[0002] A variety of analytic instruments employ regulated flows and
a number of flow paths in order to provide analyses regarding
various chemicals in processing or analytic contexts. The analytic
instruments typically function using one or more flow devices that
can initiate, interrupt, and reverse flow through the device. Such
variety of flow functions is usually provided by a combination of
one or more flow valves and/or pumps. In order to function
effectively, analytic instruments will generally include a
plurality of sample flow paths. In the context of a gas
chromatograph, a number of flow paths are used to introduce a flow
of sample and carrier gas into the gas chromatograph; flow a
controlled amount of sample across a sorbent column; reverse the
flow to elute the sample from the column; and detect the various
components in the flow stream.
[0003] Gas chromatographs generally use pneumatic multiport valves
to switch the flow of gas during analysis. These valves are
critical to establishing a flow which allows the gasses to be
separated. Among other things, it is very important that the gasses
be able to enter and exit the valve with low leakage. This has been
accomplished in the past through tube fitting connections or other
various means. It is common for multiport flow selector valves to
have 6 or even 10 individual ports, in addition to the actuation
gas ports required for pneumatic actuation. A gas chromatograph may
employ a number of such multiport selector valves. Accordingly, the
time required to couple each tube to its respective port can add up
to significant assembly time. Further, each individual tube
connection is subject to variations in operator torque, tubing
modifications, such as bending or routing, et cetera.
[0004] As the art of process analytic devices has progressed, there
is increasing pressure to provide a lower-cost, higher-performance
analytic instrument.
SUMMARY
[0005] A pneumatic multiport selector valve and analytic instrument
employing said valve are provided. The valve includes a base having
a mounting surface configured to mount to the analytic instrument.
The mounting surface has a plurality of apertures therein for
coupling to flow conduits of the analytic instrument. At least one
piston plate has a number of apertures therethrough. The apertures
are configured to slidably receive respective pistons. Pistons are
disposed in respective apertures of the at least one piston plate.
A cushion layer is disposed between at least one piston plate and
the base. The cushion layer has a plurality of apertures to allow
actuation gas therethrough. A plate clamps at least one piston
plate to the base.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a diagrammatic exploded view of a multiport flow
selector valve in accordance with the prior art.
[0007] FIG. 2 is a diagrammatic view of a portion of a gas
chromatograph employing multiport selector valves in accordance
with the prior art.
[0008] FIG. 3 is a diagrammatic exploded view of a multiport
selector valve in accordance with an embodiment of the present
invention.
[0009] FIG. 4 is a diagrammatic perspective view of a multiport
selector valve in accordance with an embodiment of the present
invention.
[0010] FIG. 5 is a diagrammatic view of a multiport selector valve
being mounted to a gas chromatograph in accordance with an
embodiment of the present invention.
[0011] FIG. 6 is a diagrammatic perspective view of a portion of a
gas chromatograph employing a plurality of multiport selector
valves in accordance with an embodiment of the present
invention.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0012] FIG. 1 is a diagrammatic exploded view of a multiport flow
selector valve in accordance with the prior art. Valve 10 includes
base plate 12 that has a mounting surface 14 that couples to an
analytic instrument, such as a gas chromatograph. Base plate 12
includes a plurality of pneumatic actuation ports 16 that couple to
a suitable source of actuation gas, such as carrier gas, compressed
air or nitrogen. Base plate 12 includes a through-hole in its
center allowing bolt 18 to pass therethrough in order to supply the
force to clamp the components of valve 10 together. The base plate
12 includes a plurality of horizontal holes used exclusively for
mounting the valve 10 to the analytic instrument.
[0013] Layers 20 and 22 comprise a lower actuator diaphragm and are
generally formed of polyimide such as that sold under the trade
designation Kapton.RTM. available from E. I. du Pont de Nemours and
Company of Wilmington, Del. Three long pistons 24 are disposed
proximate lower actuator diaphragm 22 and slidably extend into
lower piston plate 26. Upper actuator diaphragm layers 28, 30 are
preferably formed of polyimide and are disposed proximate surface
32 of lower piston plate 26. Pistons 34 are positioned proximate
diaphragm layer 30 and slidably extend into upper piston plate 36.
A cushion layer 38 is formed of a material that can absorb and/or
attenuate at least some physical motion. For example, cushion layer
38 can be formed of a meta-aramid material such as that sold under
the trade designation, Nomex.RTM. available from E. I. du Pont de
Nemours and Company. Cushion layer 38 is disposed proximate surface
40 of upper piston plate and a sealing diaphragm 42 is disposed
proximate cushion layer 38.
[0014] A pair of alignment pins 44, 46 extends into primary plate
48 and through layers 42, 38, 30, 28, 22, 20 as well as through
plates 36, 26. Alignment pins 44, 46 help maintain careful
positioning of the various components of valve 10 during
assembly.
[0015] Primary plate 48 provides the ports of the multi-port valve
10. The ports are indicated at reference numeral 50 and are
generally internally threaded to accept standard tube fittings.
Once valve 10 is fully assembled and mounted into the gas
chromatograph, it is necessary to attach tubing to the individual
ports and the pneumatic control line ports. For a gas chromatograph
having three such multiport selector valves, the assembly process
is complex and labor intensive. Moreover, if a valve needs to be
replaced, all of the discrete tubing connections for that valve
must be removed and the valve must be unbolted from the gas
chromatograph. When the valve is repaired, rebuilt or otherwise
replaced, the entire assembly must generally be recalibrated to
account for any minor variations introduced with the new/repaired
valve.
[0016] FIG. 2 is a diagrammatic view of a portion of a gas
chromatograph employing multiport selector valves in accordance
with the prior art. As illustrated, there are a significant number
of tubing connections made on the top of each multiport selector
valve along with a significant number of tubing bends.
[0017] FIG. 3 is a diagrammatic exploded view of a multiport
selector valve in accordance with an embodiment of the present
invention. Valve 100 includes base plate 102 which is substantially
different than base plate 12 of valve 10. Valve 100 includes an
internally threaded bore 104 in its center that mates with threads
of bolt 18. Guide pins 144 and 146 extend into base plate 102 and
through all other layers of valve 100 into plate 106. Seal layer
108 is disposed proximate base plate 102 and includes a pair of
apertures 110, 112 (in addition to the alignment apertures and the
center aperture) that allow actuation gas to pass therethrough.
Seal layer 108, in one embodiment, may be formed of polyimide.
Similarly cushion layer 114 includes a pair of apertures 116, 118
to allow actuation gas to pass therethrough. Cushion layer 114 is
preferably formed of a meta-aramid material such as Nomex.RTM..
However, given the porous nature of this meta-aramid material, it
is important to isolate it from the actuation gas. Thus, a pair of
o-rings 120, 122 is clamped between base plate 102 and first piston
plate 130 within respective apertures 110, 116 and 112, 118 in
layers 108 and 114. O-rings 120, 122 ensure that actuation gas
flowing into first piston plate 130 from base plate 102 will not
contact cushion layer 114.
[0018] A first set of pistons 134 is slidably received within first
piston plate 130. A pair of actuator diaphragm layers 150, 152 is
disposed between first piston plate 130 and second piston plate
154. Layers 150, 152 are preferably formed of polyimide and include
apertures for alignment pins 144, 146; pistons 124; actuation gas;
and bolt 18. A second set of pistons 124 is slidably received
within second piston plate 154. A second pair of actuation
diaphragm layers 156, 158 is positioned between second piston plate
154 and plate 106. Layers 156, 158 are also preferably formed of
polyimide.
[0019] Plate 106, unlike plate 48 (shown in FIG. 1) is devoid of
any tubing ports. Instead, fluidic connections to valve 100 are
made via mounting surface 160 on base plate 102. Surface 160
includes a plurality of apertures. Each port of multiport valve 100
has an aperture in surface 160 that aligns with and is coupled to a
fluidic connection or port in the gas chromatograph (illustrated in
FIG. 5). Further, fluidic connections for actuation gas are also
done via apertures in surface 160. Moreover, given the planar
nature of surface 160, all of the fluidic connections can be made
simultaneously as valve 100 is clamped into the gas
chromatograph.
[0020] FIG. 4 is a diagrammatic perspective view of a multiport
selector valve in accordance with an embodiment of the present
invention. Valve 100 is shown in a fully-assembled state. This is
so despite the fact that valve 100 is not yet mounted to a gas
chromatograph. In order to mount valve 100 to a gas chromatograph,
mounting screws or bolts are passed through mounting holes 170 in
flange 172. Thus, a fully-assembled valve can be provided to an end
user who can perform a simple replacement of a faulty valve without
having to disconnect and reconnect multiple threaded tube fittings
at the risk of creating leaks or causing mechanical damage to the
threads by cross-threading. Over the lifetime of a valve, various
situations may be encountered which cause the valve to fail. Due to
its unique construction, the valve can be replaced by simply
unscrewing the three retaining screws, replacing the valve with an
alternate and reattaching it.
[0021] FIG. 5 is a diagrammatic view of a multiport selector valve
being mounted to a gas chromatograph in accordance with an
embodiment of the present invention. In the embodiment illustrated
in FIG. 5, valve 100 is a six-port valve that is one of three such
valves in gas chromatograph 200. Gas chromatograph 200 includes a
base 202 having a number of internally-threaded bores configured to
mate with mounting screws or bolts 204. A pair of guide pins 206,
208, different than guide pins 144, 146, is placed within plate 202
in order to ensure proper placement of valve 100 as it is mounted
to plate 202. Plate 202 also includes ports 210 which are disposed
to mate with corresponding apertures in surface 160 of valve 100.
O-rings or other suitable structures are provided between plate 202
and surface 160 in order to ensure a leak-tight coupling. However,
it is expressly contemplated that a single seal or gasket could be
provided for such couplings in accordance with embodiments of the
present invention. Actuation gas fluid ports 212 are also
fluidically coupled to surface 160 of valve 100. In accordance with
one embodiment of the present invention, three mounting holes are
equally spaced about the perimeter of flange 172, such that the
clamping force provided by screws 204 is evenly distributed across
surface 106. Additionally, since bolt 18 is no longer used to
secure valve 100 to plate 202, the clamping force within valve 100
can be different than the clamping force between surface 160 and
plate 202.
[0022] FIG. 6 is a diagrammatic perspective view of a portion of a
gas chromatograph employing a plurality of multiport selector
valves in accordance with an embodiment of the present invention.
The gas chromatograph illustrated in FIG. 6 includes a plurality of
columns 220 and associated tubing connections. However, using
multiport selector valves in accordance with embodiments of the
present invention provides a much simpler assembly in terms of
tubing connections and routes in comparison to prior art
techniques.
[0023] Embodiments of the present invention deviate from prior
approaches in the manner in which the gasses are brought into and
out of the valve.
[0024] Although the present invention has been described with
reference to preferred embodiments, workers skilled in the art will
recognize that changes may be made in form and detail without
departing from the spirit and scope of the invention.
* * * * *